The present invention generally relates to telecommunication systems, and more particularly to remote line powering in telecommunication systems.
In plain old telephone service (POTS), telephones are remotely powered by electric power drawn from a central office (CO) and therefore supply of electric power to the telephones is independent of supply of conventional main alternating-current (AC) electric power to subscriber premises. The evolvement of new and sophisticated telephone and data services introduced new appliances including new communication interfaces at subscriber premises that also require supply of electric power and therefore the demand for remote supply of electric power has increased. One form of remote powering of communication interfaces at or near subscriber premises is mentioned, for example, in U.S. Pat. No. 6,005,873 to Amit.
However, electric power supply conveyed on each telephone line twisted pair is limited due to safety requirements. Therefore, improved ways of remotely supplying electric power to appliances at or near subscriber premises while maintaining safety regulations and standards are required.
Telecommunication standards that are used to define safety requirements in remote powering and electrical parameters are described in IEC60950-21. The disclosure of this reference as well as the disclosure of the references mentioned throughout the present specification are hereby incorporated by reference.
The present invention seeks to provide improved apparatus and method for remotely supplying electric power to appliances at or near subscriber premises while maintaining safety regulations and standards.
Further objects and features of the invention will become apparent to those skilled in the art from the following description and the accompanying drawings.
There is thus provided in accordance with a preferred embodiment of the present invention a method for remote line powering in a telecommunication network, the method including supplying electric power via a plurality of line pairs that are suitable for use in the telecommunication network, and aggregating the electric power supplied via the plurality of line pairs to provide electric power suitable for powering an appliance, characterized in that the electric power supplied via each line pair of the plurality of line pairs does not exceed a pre-defined threshold. The appliance preferably includes a communications appliance.
Preferably, the electric power supplied via the plurality of line pairs is obtained by feeding along each line pair in the plurality of line pairs direct current I at an input voltage having a value within a range from VA to VB, wherein the values of the current I and the input voltage are compliant with telecommunication standards for remote feeding of telecommunication circuits.
Additionally, the method includes the step of converting each said input voltage to an output voltage aggregated to provide an aggregate output voltage Vout that is acceptable by the telecommunication standards. Further additionally, the method includes the step of converting each said input voltage to an output voltage that is acceptable by the telecommunication standards. Each converting step preferably includes the step of converting the input voltage to the output voltage for each line pair independently from other line pairs in the plurality of line pairs. More preferably, this conversion of the input voltage to the output voltage for each line pair is done full isolation from the other line pairs.
Preferably, VAxe2x89xa750 VDC, VBxe2x89xa6320 VDC, and Ixe2x89xa660 mA. The aggregate output voltage Vout is preferably within a range from 42 VDC to 54 VDC.
The method may also preferably include the step of separately controlling the electric power supplied via each of the plurality of line pairs.
There is also provided in accordance with a preferred embodiment of the present invention apparatus for remote line powering in a telecommunication network, the apparatus including a plurality of line pair terminations terminating a corresponding plurality of line pairs that are suitable for use in the telecommunication network, the line pairs being operative to convey electric power supplied by a corresponding plurality of power sources, and an electric power aggregator operative to aggregate the electric power supplied via the plurality of line pairs to provide electric power suitable for powering an appliance, and to control that the electric power supplied via each line pair of the plurality of line pairs does not exceed a pre-defined threshold. The appliance preferably includes a communications appliance and each of the plurality of line pairs preferably includes telephone line twisted pairs.
The electric power aggregator preferably includes a plurality of separate power supervisors, wherein each separate power supervisor is operatively associated with a corresponding one of the plurality of line pair terminations.
Additionally, the electric power aggregator includes a plurality of separate controllers, wherein each separate controller is operatively associated with a corresponding one of the plurality of separate power supervisors.
Further additionally, the electric power aggregator includes a plurality of separate power stage converters, wherein each power stage converter is operatively associated with a corresponding one of the plurality of separate controllers and operative to convert an inputted voltage having a value within a range from VA to VB to an output voltage that is acceptable by telecommunication standards. More preferably, the plurality of separate power stage converters are operative in full electrical isolation from each other
The apparatus additionally includes an alarm and logic unit operative to generate an alarm indicating a low voltage output level. The alarm and logic unit may further be operative to generate an indication indicating that electric power is not received over at least one line pair.
Further additionally, the apparatus includes a disconnection unit operative to detect that an output voltage Vout resulting from aggregation of the electric power supplied via the plurality of line pairs is lower than an output voltage acceptable by telecommunication standards.
The apparatus is preferably included in a communication system that also includes the plurality of line pairs and the plurality of power sources.